Friction switch mechanism



May 19, 1931. G. H. WHITTINGHAM 1,805,377

FRICTION SWITCH MECHANISM Filed April 25, 1930 2 Sheets-Shed 1 May 19,1931. G. H. WHITTINGHAM FRICTION SWITCH MECHANISM Filed April 25. 1930 2Sheets-Sheet 2 gwwntoc Patented May 19, 1931 UNITED STATES GEORGE H.WHITTINGHAM, 0F BALTIMORE, MARYLAND FRICTION SWITCH MECHANISMApplication filed April 25,

This invention relates to switching mechanism designed to close circuitsin predetermined times and in predetermined order after the performanceof an initialoperation which starts the switch closing mechanism intooperation. In the control of electric motors, where it is desired toclose relays or contactors in predetermined times and order, delay inthe closure of the switches controlling the contactors or relays may beobtained in various ways, as b the use of thermostats, but practicaldiflicu ties arise in the use of such devices where long periods ofdelay are required in the actuation of the switches. The purpose of thepresent invention is to provide a switch closing mechanism in which aplurality of switches may be closed in any desired order and opensimultaneously, and in which a very long delay in closing the switchesis readily obtained.

In carrying out the invention, I provide a shaft which isrotated at avery slow and constant speed; a series of stationary switch members, aplurality of switch members 25 loosely journaled on the shaft and havingcontacts adapted to engage the stationary members, each movable memberbeing biased away from the stationary members and adapted to rock freelyon the shaft into engagement with a fixed stop; friction disks ofconducting materialrotatable with the shaft and arranged on oppositesides of the movable switch, members, and means for clamping said disksagainst the movable switch members to cause the latter to move with theshaft in the direction to close the switches. Each movable member has acontact arm which is adjustable toward and from the opposing stationaryswitch member, to vary the order in which the several switches willclose and the time of closure. The shaft rotates very slowly and at aknown speed, so that by adjusting the contact on the movable member thetime of closure may be accurately pre-set. As each movable switch membercloses against a stationary member the movable member stops, while thefriction disks which engage it continue in operation holding the switchclosed. When it 5 is desired to open the switches, the friction PATENTOFFlCE disks are released from the movable switch members and the latterthen rock on the shaft to their initial positions against a fixed stop.

In the accompanying drawings, Fig. 1 is a front elevation of themechanism;

Fig. 2 is a section on the line 22 of Fig. 3; Fig. 3 is a frontelevation of the appa- 1930. Serial No. 447,317.

ratus, theshaft which operates the switches are secured forwardlyprojecting metal bars 2 and 3, spaced apart from one another and formingsupports for the working parts of the apparatus. A. tubular shaft 4extends horizontally through these bars and is journaled therein, d uponthis shaft is mounted a wormv w 7. which is geared to a small electricmotor 6 by reduction gearing which causes the worm wheel and shaft t toturn at a very low speed when the motor is in operation. The motor ispreferably a shuntwound motor which operates at con- 1/ speed. A numberof friction disks a, a, a and a are mounted upon the shaft 4, so

to turn with it, but these disks are movable relatively to oneanotherlongitudinally of the shaft. The friction disks are composed ofelectrically conductive material, preferably carbon-graphitecomposition, molded into the desired shape. The shaft is provided with alongitudinal slot 7, which serves as a keyway into which keys 8, in thefriction di ks, extend. The key 8, in the disk a, ex tends completelythrough the slot and proects slightly into the bore of the shaft, whilethe keys on the other disks are shorter and do not extend into the bore.The webs 9 of the friction disks are formed with central openshaft andto rock laterally-to a slight extent,

ing the disk. 1o

Between the friction disks are mounted contactmembers-b, b and 6 eachcontact member comprisii'ig a ietal plate 11, having a central opening12, through which the tubular shaft extends. The plates are in the formof disks which, for about one-half of their circumferential lengths,project radially beyondthe peripheries of the friction disks, and theprojecting portion of each plate has a flange 13 which projects atopposite sides of the plate- This flange, on each plate,

, forms a support and guide for an adjustable contact arm. A U-shapedclamp or yoke 14 fits around the flange of the member 6 and a contactarm 15 has a short right-angled portion :0, which is clamped against theperiphery of the flange by a set screw 16 at the center of the clamp oryoke. The contact arm 15 extends in an approximately radial directionfrom the flange and is adaptedto engage a stationary contact member 0,which is mounted upon the switchboard. Similarly, contact arms 15 and 15are adjustably secured to the flanges of-the members 6 and b by clamps14 and 14 respectively, and these members 15 and15 are adapted to engagestationary contacts 0" and 0?, respectively. A weight'17 project'sradially from the member bat one end of its flange, and similarlyarranged weights 17 and 17 project from the members b"and 6 Theseweights tend to rockthe plates to which they are attached so as to holdthe contact arms out of engagement with the stationary contact members,and normally these weights rest against a strip of insulating material18 whichis supported by a bracket 19 connected to the insulating base 1.p The edge of the strip 18, which the weights rest against, is parallelwith the axis of the shaft 4.

A rod 20 extends longitudinally through the shaft ,4 and is providedwith a head 20 at one end, and between said head and the friction disk ais a metal clamping disk 21 of the same diameter as the disk a The rod20fits freely in the bore of the shaft 4 and is movable longitudinallytherein so that if the rod 20 is moved to the right in Fig. 1, it

will cause the clamping disk 21 to bear against the friction disks a andthe several friction.

ing bars2 and .3 by an iron plate 22, which is secured to said bars, andhas a downwardly turned part 22 in which an armature 23 shown in Figs. 1and 3. :normally held in this position by a spring 25 is pivotallymounted. This armature has an arm 24' which projects upwardly and has anopening through. which the right hand end portion of the shaft 20extends. The shaft 20 has a shoulder 20 and when the magnet rod inposition to release the friction disks, as

which is coiled upon a stud 26, the latter'projecting horizontally fromthe arm 22 on the.

support 22 through an opening in the arm 24. The arm 24 constitutes alever for moving the shaft 20. On this lever, midway between the shaft20 and the spring 25,;a projection 27 isv provided and this formsafulcrum for another lever 28, the lower end of which is interposedbetween the spring 25 The armature is so i and the lever 24. The upperend of the lever 28 has an opening through which the shaft 20 extendsand this end of the lever ears a ainst a washer 29 which is held inplaceby a cotter pin 30, passing through the shaft 20.

When the armature 23 is lifted by the magnet, the lever 24 swings awayfrom the shoulder 20 and pressure is applied to the central part of thelever 28 at the fulcrum 27. As the spring 25 bears against the lower endof the lever 28, the upper end of said lever applies a yielding pressureto the rod 20, tending to force it to the right to. clamp the fries tiondisks against the plates or themova'ble switch members. WVhen thearmature '23 drops, the lever 24 swings to the left, releasing thepressure atthe' center of the lever 28, and the lever 24, bearingagainst the shoulder 21, moves the rod 20 tothe left, releasing thepressure of the friction disks figainst theplates of the movable switchmemers.

V In order to avoid any adhesion of thefrice tion disks to the plateswhen the rod is moved to unelamp the disks, I provide a collar 20 on therod 20 which strikes the longtooth or key 8 in the friction disk a, whenthe rod 20 is moved to the left by the lever 24, and the jar given to.the disk at is imparted to the other disks and the plates, insuringtheir immediate separation.

A conductor 31 is shown connected to the supporting bar 3 and all of themovable parts of thev apparatus are electr'cally connected to thissupport and wire 31. Conductors 32,

33' and 34 are shown connected to the stationary contact members 0, 0',and 0 ,respective1y. The coil of the magnet may be connected to the;current source in any desired way, according to the use which is to bemade of the apparatus.

The shaft 4 turns the clockwise direction when viewed from its righthand end, while the weights on the movable switch.

members tend to rock said members on the shaft away from the stationaryswitch members. Normally, the movable members are held out of engagementwith the stationary members by the weights on the former, which restagainst the stop 18. The motor may run constantly, or it may be switchedinto and out of circuit, as desired, according to the purpose for whichthe apparatus is used.

The contact arms will beset on the movable contact members at anydesired distance from the stationary contacts according to the delaydesired in closing the switches. Assuming the motor to be running andthe contact arms to be set on the contact members as shown in Figs. 1and 2, if the magnet d is energized, it will attract its armature 23 andthe lever 24, connected to the armature, will pressthe lever 28 to theright and this latter lever will move the rod 20 in the direction todraw the metal disk 21 against the adjacent friction disk a and causethe movable contact members b, I) and b to. be clamped between thefriction disks a, a, a and a As the friction disks slowly rotate, thecontact arms 15, 15 and 15 will engage the stationary contacts 0, c and0 respectively, in succession. As each arm engages a stationary contactthe metal plate to which the arm is connected stops while the frictiondisks on either side of the'plate continue to rotate. WVhen it isdesired to open the switches the circuit of the magnet cl is broken'andthe armature of the magnet drops, causing the lever 24 to be moved bythe springs against the shoulder 2O on the rod 20, and the rod isthereby moved to the left. When the rod 20 is moved to the left, thepressure of the clamping disk 21 against the friction disk a is relievedand the collar or tappet 20 ja-rs the disks and plates loose. When thisoccurs, the weights on the movable contact members immediately rock saidmembers about the shaft until the weights on. said members engage thestop 18. The contact arms on said members are thus returned to theiroriginal pre-set positions.

As the friction disks, of carbon-graphite composition, are electricallyconductive and mounted upon a metal shaft which is connected through itshearings to the current source, good electrical contact is made throughthe friction disks to the movable switch members when they are clampedbetween the friction disks. Friction disks of impregnated wood might besubstituted for the carbon-graphite disks, but in that event it would benecessary to provide flexible electrical' connections to the movableswitch members, which would not be desirable.

' l/Vhat I claimis:

1. In an electric slip-switch mechanism, a

upon the shaft and having a. contact adapted to engage said stationarycontact, said movable member being biased to open position, frictiondisks on opposite sides of said body, said disks secured to the shaft soas .to rotate therewith and being relatively movable longitudinally ofthe shaft, and means for clamping said disks frictionally against saidbody to cause rotation of the movable member to closed position.

2. In an electric slip-switch mechanism, a shaft, means for rotating theshaft, a stationary switch-member, a movable switch member comprising ametal body journaled upon the sh aft and having a contact adapted toengage said stationary contact, said movable mem her being biased toopen position, friction disks of carbon-graphite composition on oppositesides of said body, said disks secured to the shaft so as to rotatetherewith and being relatively movable longitudinally of the shaft, andmeans 'for clamping said-disks frictionally against said body tocauserotation of the movable member to closedposition. a

3. In an electric slip-switch mechanism, a shaft, means for rotatingthe" shaft, a plurality of stationary switch members, a plurality ofmovable switch members eachv comprising a metal body journaled upon theshaft and having a contact adapted to engage one of said stationarycontacts, said movable members being biased to open positions, frictiondisks on opposite sides of the several bodies, said disks secured to theshaft so as to rotate therewith and being relatively movablelongitudinally of the shaft, andmeans for clamping said. disksfrictionally against said bodies to cause rotation of the movablemembers to closed positions. r

4. In an electric slip-switch mechanism,- a

shaft, means for rotating the shaft, 2. plurality of stationary switchmembers, a plurality of movable switch members each comprising a metalbody journaled upon the shaft and having a contact adapted to engage oneof said stationary contacts, said movable members being biased to openpositions, friction disks of carbon-graphite composition on oppositesides of the several bodies, said disks secured to the shaft so as torotate therewith and being relatively movable longitudinally of theshaft, and means for clamping said disks frictionally against saidbodies to cause rotation of the movable members to closed positions.

5. In an electric slip-switch mechanism, a shaft, means for rota-tingthe shaft,a plurality of stationaryv switch members, a plurality ofmovable switch members each comprising. a plate loosely journaleduponthe shaft and having a contact surface adapted to engage one of saidstationary members, said movable members being biased to open positions,a stop for limiting the'free rotation of the several plates, frictiondisks on.

opposite sides of theseVer-al plates, said disks of the shaft, and meansfor clamping said disks frictionally against the plates to causerotation of the movable members'to closed positions.

e 6. In an electric slip-switch mechanism, a shaft, means for rotatingthe shaft, a stationary switch member, a movable switch membercomprising a metal disk loosely journaled upon theshaft and a contactadjustable on said disk toward and from the stationary switch member,said movable member being biased to open position, friction disks onopposite sides of themetal disk, said friction disks securedto the'shaftso as to rotatetherewith andbeing relatively movable longitudr nally ofthe shaft, and means for clamping said-friction. disks against the metaldisk to cause rotation of the movable member to closedposition. i r 1 7.In an electric slip-switchmechanism, a shaft,'means for rotating theshaft, a stationary switch member,a movableswitch member comprising ametal disk loosely journaled upon the shaft and having a peripheralflange and a contact adjustably mounted on said flange, a stop forlimiting thefree rotation of said metal disk, friction disks ofcarbongraphite composition on opposite sides of the metal disk, saidfriction disks secured to the shaft so as to rotate therewith and beingrela-- tively movable longitudinally of the shaft, andmeansfor clampingsaid friction disks against the metal disk to-cause rotation of themovable; member to closed position,

8. Inan electric'sli'p-switch mechanism, a"

shaft, means for rotating the shaft, a station ary switch member, amovableswitch member comprising a metal disk loosely journaled upon-theshaft and having a contact and a weighted arm, said arm tending torockthe,

movable member to open position, a stop adapted tobe engaged by said armto limit the free rotation of the metal disk, friction disks ofcarbon-graphite composition on opposite sides of the metal disk, saidfriction disks secured to the shaft so as torotate there with. and beingrelatively movable longitudinally of the shaft, and means for clampingsaid friction disks against the metal disk to cause rotation of themovable member to closedposition. V I

9. In an electric slip-switch mechanism, a tubular'shaft, means forrotating the shaft, a stationary switch member, a movable switch membercomprising a metal plate loosely journaled upon the shaft and having acontact adapted toengage said stationary member, said movable memberbeing biased to open position, a stop for limiting the free rotation ofthe plate, frictiondisks of carbongraphite composition on opposite sidesof the rotate therewith and being relatively movable longitudinally ofthe shaft, and means for clamping said friction disks against the platecomprising a rod extending through the bore a of saidshaft, a clampingdisk mounted on said rod and adapted to engage'one ofthe friction disks,anelectromagnet, and means operated by the magnet for moving said rodendwise to cause the clamping disk topress the friction disks againstthe metal plate.

10. In an electric slip-switch mechanism,

a shaft, means for rotating the shaft, a stationary switch-member, amovable switch member. comprising ametal body journaled upon theshaftand having a contact adapted to engage saidstationary contact, saidmovable member beingbiased' to open position, friction disks on oppositesides ofsaid body, said disks secured to the shaft so as to rotatetherewith and being relatively movable longis tudinally of theshaft,meansfor clamping said disks against the plate and for releasingthe disks, and means for jarring said disks and metal body when theyhave beenreleased.

11. In an electric slip-switchmechanism, a

tubular shaft, means for rotating the shaft, a

stationary switch-member, a movable'switch member comprising a metalbody journaled upon the shaft and having a contact adapted to engagesaid stationary contact, said movable member being biased to openposition,

friction disks on opposite sides of said'body,

said disks secured to the shaft soas' to rotate therewith and beingrelatively movable longitudinally of the shaft, a rod extending throughthe bore 'of the shaft, a clamping disk on thejrodadapted to engage oneof the friction disks, means for moving said rod to clamp and unclampthe disks, and means on the rod'for arring the disks when the rod ismovedflto unclamp the disks; I 7

12. An electric slip-switch mechanism comprising a shaft, means forrotating the shaft, a stationary switchmember, a movable switch memberjournaled upon the shaftjand biased to open position, friction devicescarried. by the shaft on opposite sides of the movable member andpositively driven by the shaft, a stop for limiting the opening movementof the latter member,,and means for clamping said devices against themovable member and for releasing said devices, I

, 13. An electric slip-switch m'echanism comprising a shaft, means for"rotating the shaft, a stationary switch member, a movable switch memberjournaled upon the shaft and biased to open position, a contactadjustableonthe latter'member, and means. for clamping said releasingsaiddevices.

movable member toward and from the stationary member, friction devicescarried by the shaft on opposite sides'of the movable 7 member andpositively drivenby the shaft, a stop for limiting the opening movementof the

